I've worked with AWS to do heavy numerical processing (running scripts on data for weeks). Fortran and python on large datasets.
I'm a hydrogeologist (also GIS+Database manager many years ago when QGIS wasn't on the map, pardon the pun), I'm not formally trained in IT. I learn more everyday and I'm keen to learn how to use AWS for data workflows like yours.
I've used PostgreSQL / PostGIS locally but there's still plenty for me to learn about it too. I've set it up so I can manage it from python for some particular tasks.
I should say thanks again because you didn't only do the work, you documented it really nicely. Short and to the point, including a nice diagram. I'm sure it will help me in the future handling groundwater data from the same NSW servers.
J